Soyabean is a leguminous vegetable of the pea family that grows in tropical, subtropical, and temperate climates. Soybean was domesticated in the 11th century BC around northeast of China. It is believed that it might have been introduced to Africa in the 19th century by Chinese traders along the east coast of Africa.
The plant is classed as an oilseed rather than a pulse by the UN Food and Agricultural Organization (FAO). Soy varies in growth and habit. The height of the plant varies from less than 0.2 to 2.0 m. The pods, stems, and leaves are covered with fine brown or gray hairs. The leaves fall before the seeds are mature. The crop can be successfully grown in many states in Nigeria using low agricultural input. Soybean cultivation in Nigeria has expanded as a result of its nutritive and economic importance and diverse domestic usage.
The most nutritious and most easily digested food of the bean family, the soybean is one of the richest and cheapest sources of protein. Government sources estimate that about 25 percent of Nigeria's domestic production is consumed directly in rural areas as human food. It is a staple in the diet of people and animals in numerous parts of the world today. Many leguminous crops provide some protein, but soybean is the only available crop that provide high quality source of protein comparable to meat, poultry and eggs.
Soybeans vary in protein from 24-45%. Soybeans vary in oil from 17-35%. Thus the different cultivated varieties can taste quite different from one another. Soybean oil; an extract from the seed is a major source of healthy oil in the world. It is also processed into soy ice cream, soy yogurt, soy cheese etc.
A by-product from the oil production (soybean cake) is used as a high-protein animal feed in many countries. Soybean also improves soil fertility by adding nitrogen from the atmosphere. This is a major benefit in African farming systems, where soils have become exhausted by the need to produce more food for increasing populations, and where fertilizers are hardly available and are expensive for farmers.
In Nigeria, soybean cultivation starts in May/June. Soybeans grow well on almost all types of soil, with the exception of deep sands with poor water retention. The optimal soil pH is 6.0 to 6.5, therefore liming may be required. With respect to climate, the soybean grows best in temperate zones. The soybean is a so-called short-day plant, meaning that flowering occurs when the nights begin to lengthen. The breeding of varieties with different maturation periods (maturity groups) has permitted optimal production in a wide range of latitudes. Rainfall in the range of 500 to 700 mm. is required for good yields. Adequate water supply is especially important during the period of pod and seed development (pod filling stage). Irrigation is now considered an essential factor for increased profit and security to the farmer.
PEST & DISEASES
Diseases prevalent in soybean production in Africa include rust, red leaf blotch, frog-eye leaf spot, bacterial pustule, bacterial blight, and soybean mosaic virus. Pests include pod (stink bugs) and foliage feeders, bean flies and nematodes. Soybean rust, caused by the Phakopsora pachyrhizi fungus, attacks and destroys the leaves of the plant and can cause up to 60% yield loss.
Other problems include pod shattering that reduces seed longevity, and production and distribution difficulties.
This normally commences in late October and runs through November every year. The crop is harvested 3 - 4 months after planting, depending on the time of sowing and seed variety. Early-maturing types can be harvested for grain 70 days after planting and late-maturing needs up to 180 days. Soybeans can be harvested by hand or by combined harvesters (this only at full maturity or after windrowing - cutting plants and leaving them in rows for wind and sun to dry properly).
Soybean is mature for harvest when most leaves have aged and turned yellow at least one pod per plant has turned brown or black. The pods are still green yet filled with seeds for vegetable soybeans. Take the following steps when harvesting soybeans:
The plants are cut near the ground or pulled with their roots once threshed
Dry the soybeans to below 12 % moisture content before storing.
Keep in a clean store and prevent weevil attack by any of the means described under storage pests.
As human population increases, so does our need for protein. As we grow from babies to adults, we have a great primary requirement for protein. Worldwide consumption of soybean is nearly 11 million tons. Africa consumes about 618,000 tons annually, and uses another 4,800 tons for animal feed. Nigeria is the largest consumer of soybeans in sub-Sahara Africa followed by Uganda. It is an excellent sources of high quality protein and has a low saturated fat, with no Cholestrerol and a great amount of dietary fibre, making it the best dietary choice to reduce risk of cardiovascular diseases.
Nigeria currently produces soybean worth $85 million in the international market and though most of the nation’s soybean is consumed locally where they are used in the production of soymilk and specially formulated foods to help malnourished infants and children, the international market for the product is growing and sustainable.